Jack-screw



w; H. WILLIAMS.

Jack Screw. No. 235,481.

Patented Dec. 14,1880.

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NJHERS, PHOTO-LITHDGRAPRER, WAsmNGTqN, DXC.

UNITED STATES PATENT OFFICE.-

WILLIAM H. WILLIAMS, OF KEY WEST, FLORIDA.

JACK-SCREW.

SPECIFICATION forming part of Letters Patent No. 235,481, dated December 14, 1880.

Application filed October 1, 1880.

To all whom it may concern Be it known that I, WILLIAM H. WILLIAMS, of Key West, in the county of Monroe and State of Florida, have invented anew and Improved J ack-Screw, of which the following is a specification.

This invention relates to that class of devices that are designed for lifting heavy bodies.

The invention consists in a peculiarly-constructed pawl, made detachable and combined with a'bifurcated lever provided with side bolts, as hereinafter described.

Figure 1 is a partly-sectional vertical elevation of the device. Fig.2 is a longitudinal elevation of the pawl. Fig. 3 is a cross-see tion of the ratchet, showing its attachment to the screw.

Similar letters of reference indicate corresponding parts.

In the drawings, A represents the base-block of the device, provided on its under side with pointed studs a a, to hold it in place, and provided,-also, with ahemispherical recess, b, for convenience of fitting the washer and pin 0 d respectively on the lower end'of the screw B, whereby th'e said screw B is held in an upright position.

B is a square threaded screw, provided with a square shank, as shown at f, below the screwthreads, on which shank f is fitted the ratchet O; and immediately below the square portion f the screw-shank is round for a short space,

as shown at g, and then turned down to forui a spindle, h, that is inserted through the center of the base A, and has the washer c secured upon it by the pin d, as aforesaid. The shoulder i, formed by turning down the spindle h, rests on the top of the base A, and also serves to support the screw Bin an upright position. D is a bifurcated rotatable lever-socket, provided with collars k k, encircling the screwB above and below the ratchet O, and provided (No model.)

with a detachable pawl, F, that is hooked on a vertical bolt, m, and held against the ratchet O bya spring, E, which is secured on the handle D of the lever-socketD by a thumb-screw, E. This pawl F is provided with an inner concave surface, as shown at q, so that the teeth of the ratchet 0, working against said pawl F, will easilyrelease it, so that the spring E may press it into the interspaces between said ratchet-teeth and said pawl F is also provided with a curved slot, 1, by means of which it is engaged or hooked on the bolt m. Both sides of the lever D are provided with bolts m, so that, a reverse action of the jack-screw bein g required, the pawl F can be unhooked from one bolt on and hooked upon the other bolt m, and the said pawl F can at any time be removed altogether from the device to insure that the said jack-screw, when in operation, shall not be tampered with by unauthorized persons.

G is a long cylindrical screw nut or cap, having a solid flat flanged head, the face of which is provided with pointed studs 0 o, for the better holding of said cap Gr against all objects resting on it. Intcriorly said cap G is screw-threaded, as shown at 1), in its lower portion, that it may move by the turning of the screw B. The interior of the upper portion of the cap G is made with a smooth bore, as shown at 8.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent- In a jack-screw, the combination, with the bifurcated lever D, provided with bolts m, of thedetachable slotted pawl F, substantially as and for the purpose described.

WILLIAM HENRY WILLIAMS.

Witnesses:

W. O. MALONEY, J r., HENRY WILLIAMS. 

